The known capsules for use in known brewing machines are disposable and single-dose containers comprising an external casing, made of liquid- and gas-impermeable plastics and having the shape of a glass or a cup. In particular, the casing has a bottom wall and a side wall defining a cavity provided with an upper opening through which the product can be inserted from which the beverage can be obtained. The upper opening is hermetically sealed by a cover, typically an aluminum or plastic film sheet, so as to seal the product inside the container cavity. The capsule is perforable to allow the inflow of pressurized liquid, typically water, and the exit of the obtained beverage. In particular, the cover and the bottom wall of the casing are perforable by suitable means of the brewing machine, to allow the delivering from the top of the pressurized liquid and the extraction from the bottom of the beverage, respectively.
A drawback of the known capsules disclosed above is that they can be used only in brewing machines provided with a special delivering circuit comprising an extracting arrangement suitable to perforate the capsule bottom to allow the outflow of the beverage, and a duct arrangement suitable to convey the beverage to the fruition container (for example, a mug, a cup, a glass, etc.). Such a delivering circuit makes the machine structure more complex and expensive. Furthermore, since such delivering circuit is in contact with the delivered beverages, it should be suitably washed after each delivering operation, both for hygienic reasons, and not to compromise the taste and quality (organoleptic qualities) of a beverage that is subsequently delivered (for example, an aromatic infusion delivered after a coffee). However, a washing arrangement of the delivering circuit is not always present in the known machines, due to their manufacturing complexity and costs.
The known brewing machines further comprise a supply circuit provided with an injecting arrangement (typically, needles or sharpened nozzles) providing to perforate the cover and deliver the pressurized liquid coming from a pump and/or a boiler.
During the production operative step of the beverage, the injecting arrangement can contact the product and/or the beverage, thus getting contaminated. As the delivering circuit, the injecting arrangement of the supply circuit should be suitably washed after each delivering operation, due to hygienic reasons, and to not compromise the organoleptic properties of a beverage delivered at a later moment.
The known capsules disclosed above allow to obtain a final product by percolation of the liquid through the initial product (typically, coffee) or by solubilization or dissolution of the initial product (for example, tea, infusions, etc.).
In the case of soluble products, due to the generally reduced volume of the capsule, it is sometimes necessary to dilute the final product by adding further liquid and continuously mixing the mixture. However, such operation cannot be carried out in an automatic manner using the known capsules and brewing machines, but it has to be carried out manually by the user.
In the case of products to be percolated, typically coffee or barley, it is necessary to ensure a suitable compression and compaction of the initial product (powdery, with a variable particle size) inside the capsule to prevent the formation of preferred passage pathways of the fluid during the percolation. Such preferred passage pathways determine, as it is known, a partial, incomplete diffusion of the fluid F through the mass of initial product P with the result of a final beverage B (coffee) with a poor quality and with unsatisfactory organoleptic characteristics.